In modern communication networks, as deployed for example in the field of automation, it is necessary for messages to be exchanged quickly between parts (switching elements) of the communication network, such as the control system, drives, sensors, etc. This exchange can take place in particular in a collision-free manner and therefore in a real time-compatible manner, if the path of each message through the network connecting the system components of the communication system and the send times of the messages are determined beforehand. In this manner the arrival time of the message at each switching element is known a priori and the switching element can forward the message according to the planned path, without addresses having to be interpreted or conflicts having to be resolved.
Of importance for such a procedure is a planning tool, which automatically determines and in particular optimizes message paths through the communication network (routing). The purpose of optimization here is to minimize the processing time for the overall message time.
A method as described above in a collision-recognition based network is disclosed in the PCT application WO 03/039082 A1. One disadvantage of the method indicated there is however that each message is sent just once per processing cycle, which results in sub-optimal utilization of the available bandwidth.